For analyzing technical processes, such as industrial manufacturing processes, it is already known to detect measuring data from the process as well as images of the process and to display these on-line or off-line.
In the case of EP 1 312 990 A2, for disruption analysis or monitoring of a technical plant, measuring data from the plant and image data relating to a mechanical movement sequence of the plant are transmitted to a controller and provided with a time stamp therein. This time stamp establishes the exact detection time of the data and allows the image data and the measuring data for analysis of the technical plant to be displayed and/or processed further in a time-synchronous manner.
The abstract of the published Japanese patent application JP 2001 125612 A also discloses the detection of image data from a production unit and of data of a PLC (Programmable Logic Controller) in a central detection unit and the provision of said data at this location with a time stamp to allow subsequent time-synchronous analysis of said data.
In a technical plant with decentralized units that are widely spaced apart the sequence over time of the measuring and image data detected by the individual decentralized units is important for the analysis of the technical process. Highly accurate analysis of the sequence over time of the data generated by the measuring and image detection units is necessary in particular in the case of a disruption to determine the trigger cause.
This applies in particular to high-speed technical processes, such as manufacturing processes for continuous material, such as paper and plastic films, for which measuring data and image data detection in the millisecond range, even better in the microsecond range, is necessary owing to the high speed of the material (for example 180 km/h in the case of a paper web in a paper machine).
However, with measuring and image detection units that are located a long way (for example several hundred meters or more) from the central detection unit there exists the problem that, for example owing to the different running times of the data from the decentralized measuring and image detection units to the central detection unit, time stamping exhibits a certain indistinctness, so sometimes a clear statement on the sequence over time of the data issued by the measuring and image detection units is not possible. This leads to indistinctness in the time-synchronous allocation of the image data to the measuring data. The different running times can be caused by the length of the transmission paths but also by devices connected into the transmission paths.